The invention relates to an apparatus on a spinning works preparation machine, e.g. a draw frame, flat card, combing machine or the like, in particular a double-head draw frame.
In the textile industry, draw frames are often used to even out the card sliver. A very simple and cost-effective variant is a machine having two drafting systems working in parallel, what is known as a double-head draw frame. In these machines, which inter alia have two feed creels and two can coilers or can changers, the working elements of the two sides are driven in each case by a common drive. The result of this, however, is that in the event of a fault on one of the two sides, both sides have to be shut down. This in turn means that although the looms are relatively cost-effective, the achievable efficiency compared with other looms is very low.
A double-head draw frame is known from DE-A-31 33 436, in which a motor drives a variable speed gear mechanism and a releasable, electrically operable coupling is arranged between the driving belt pulley of the variable speed gear mechanism and the main shaft. In the event of a fault, the motor is switched off, the coupling is activated and a brake is engaged. Through the coupling, the brake needs to decelerate only the main shaft and elements driven thereby, and not the motor with its relatively large inertia. In this apparatus, the two heads of the draw frame are mechanically coupled rigidly to one another. They may be isolated from the drive motor by means of the coupling, but only both at the same time. In the event of a fault in one of the draw frame heads, there is no provision in DE-A-31 33 436, and it is also impossible with the known device, to allow the other draw frame head to continue production. The effectiveness and efficiency is in that way limited in the known apparatus. In addition, only one coupling is provided.